Usage of digital communications networks such as the Internet continues to expand at a very rapid rate. One feature of the Internet that has led to its widespread adoption is its convenience in identifying destination hosts on the network. Computers generally address each other using numeric addresses that can be expressed in binary, hexadecimal, decimal or other numeric form. The well-known Internet Protocol (IP), for example, identifies computers communicating on a network by a unique four-byte address. These IP addresses are commonly expressed in human terms as four decimal numbers separated by periods, e.g. “192.0.23.256”. These addresses, while useful to computers, are generally very difficult for most humans to remember.
As a result, the domain name services (DNS) system has been developed and widely deployed to map numerical addresses used by computers to names that are more easily remembered by people. If a user wishes to contact a particular host on the Internet (e.g. “www.echostar.com”), for example, the user's computer contacts a DNS server on the network to request the numeric address for that host (e.g. “205.172.147.51”). The user's computer can then use the numeric address to contact the relevant host on the network.
Although the Internet already links billions of users and nodes worldwide, additional communications links are continually designed and deployed into the marketplace. Satellite links, for example, have shown great promise in providing access to communications networks in a convenient wireless manner. Satellites are typically capable of delivering very high data throughput levels across a wide service area without requiring significant infrastructure (e.g. cables or land based routers) to be in place. As a result, there is significant interest in providing data access to the Internet or another network via satellite links.
Satellite communications have a known disadvantage in inherent latency. In the case of geo-synchronously orbiting satellites, for example, the distance for the signal to travel into space and back to earth can be significant, taking half a second or so to complete the round-trip even at the speed of light. As a result of this inherent feature in satellite communications, the user at the remote end of the satellite connection can experience significant delays for certain tasks. A conventional DNS query for an address of a remote host, for example, typically involves transmitting a query to a DNS server across the satellite link (250 ms) and receiving the reply from the DNS server across the link (another 250 ms), thereby creating a delay of a half second or so to complete the query. This delay time can be frustrating to the end user.
It is therefore desirable to create systems and techniques for efficiently resolving domain name services queries across satellite or other links. These and other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background section.